An organic electroluminescence (EL) element, which emits light by using an organic EL phenomenon of an organic material, includes an organic layer in which an organic hole transport layer and an organic luminous layer are laminated between an anode and a cathode. The organic EL element has been receiving attention as a light-emitting element capable of achieving high-intensity light emission through low-voltage DC driving. However, in a display unit (an organic EL display unit) using this organic EL element, deterioration of the organic layer in the organic EL element occurs due to moisture absorption, leading to a decrease in light emission intensity or instability of light emission in the organic EL element, for example. Therefore, this type of display unit has disadvantages such as low stability over time and a short life.
Thus, Japanese Unexamined Patent Application Publication No. 2002-93576, for example, has proposed an organic EL display unit in which a cover material for the purpose of sealing is provided on an element-formation-surface side of a substrate, on which side an organic EL element and other circuits are formed, and an edge section between the substrate and the cover material is sealed by a sealant. JP2002-93576A has also proposed a configuration in which the outside of the sealant is covered with a hard carbon film serving as a protective film that prevents entrance of water vapor and the like. This configuration makes it possible to completely shield the organic EL element formed on the substrate from the outside, and prevent entrance of substances such as water and oxygen which accelerate deterioration caused by oxidation of the organic EL element.
Further, there has been also proposed an organic EL display unit of a complete solid type in which a cover material for the purpose of sealing is adhered to an element-formation-surface side of a substrate with an adhesive interposed therebetween, on which side an organic EL element and other circuits are formed.
Furthermore, there has been also proposed an organic EL display unit in which a separation groove, which separates an organic insulating film into an inner region side and an outer region side thereof, is formed at a position surrounding a display region (i.e. on an outer edge side of the display region). See, for example, Japanese Unexamined Patent Application Publications No. 2006-54111 and No. 2008-283222. Providing this separation groove prevents water, which is present on the outer region side in the organic insulating film, from entering the inner region side (i.e. a display region side) by passing through the inside of this organic insulating film. Therefore, it is possible to suppress deterioration of an organic layer (an organic EL element) resulting from the passage of the water, which is left in the display unit, through the organic insulating film.